Method for making diaphragm

ABSTRACT

A method for making a diaphragm is disclosed. The method includes the steps of: providing a carbon nanotube film structure; soaking the carbon nanotube film structure with a polymer; and carbonizing the carbon nanotube film structure infiltrated in the polymer, the polymer being carbonized to an amorphous carbon structure.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 12/824,335, filed Jun. 28, 2010, entitled,“DIAPHRAGM, METHOD MAKING THE SAME AND LOUDSPEAKER USING THE SAME,”which claims all benefits accruing under 35 U.S.C. §119 from ChinaPatent Application No. 200910110321.6, filed on 2009/10/23, in the ChinaIntellectual Property Office.

BACKGROUND

1. Technical Field

The present disclosure relates to a diaphragm, a method making the same,and a loudspeaker using the same.

2. Description of Related Art

An electro-dynamic loudspeaker typically includes a diaphragm, a bobbin,a voice coil, a damper, a magnet, and a frame. The voice coil is anelectrical conductor and is placed in the magnetic field of the magnet.By applying an electric signal to the voice coil, a mechanical vibrationof the diaphragm is produced by the interaction between theelectromagnetic field produced by the voice coil and the magnetic fieldof the magnets, thus producing sound waves by kinetically pushing theair. The diaphragm will reproduce the sound pressure waves,corresponding to the electric signals.

To evaluate the loudspeaker, a sound volume is a decisive factor. Thesound volume of the loudspeaker relates to an input power of theelectric signals and the conversion efficiency of the energy. However,when the input power is increased to certain levels, the diaphragm coulddeform or even break, thereby causing audible distortion.

What is needed, therefore, is to provide a diaphragm and a loudspeakerusing the same with high strength and Young's modulus.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiments can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the embodiments. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a schematic structural view of an embodiment of a loudspeaker.

FIG. 2 is a cross-sectional view of the loudspeaker of FIG. 1.

FIG. 3 is a schematic structural view of an embodiment of a diaphragm.

FIG. 4 is a cross-sectional view of the diaphragm.

FIG. 5 is a magnification of a cross-sectional view of a part of acarbon nanotube composite structure of the diaphragm.

FIG. 6 shows a Scanning Electron Microscope (SEM) image of a flocculatedcarbon nanotube film.

FIG. 7 shows an SEM image of a pressed carbon nanotube film.

FIG. 8 shows an SEM image of a drawn carbon nanotube film.

FIG. 9 shows an SEM image of a carbon nanotube film structure consistingof a plurality of stacked drawn carbon nanotube films.

FIG. 10 is a schematic structural view of an embodiment of aloudspeaker.

FIG. 11 is a schematic structural view of an embodiment of a diaphragm.

FIG. 12 shows an SEM image of an untwisted carbon nanotube wire.

FIG. 13 shows an SEM image of a twisted carbon nanotube wire.

FIG. 14 is a flowchart of the method for making a diaphragm according toone embodiment.

DETAILED DESCRIPTION

The disclosure is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that referencesto “an” or “one” embodiment in this disclosure are not necessarily tothe same embodiment, and such references mean at least one.

Referring to FIG. 1 and FIG. 2, one embodiment of a loudspeaker 100 isshown. The loudspeaker 100 includes a frame 110, a magnetic circuit 120,a voice coil 130, a bobbin 140, a diaphragm 150 and a damper 160.

The frame 110 can be mounted on an upper side of the magnetic circuit120. The voice coil 130 can be received in the magnetic circuit 120. Thevoice coil 130 can wind around the voice coil bobbin 140. An outer rimof the diaphragm 150 can be fixed to an inner rim of the frame 110, andan inner rim of the diaphragm 150 can be fixed to an outer rim of thebobbin 140 placed in the magnetic circuit 120.

The frame 110 can be a truncated cone with an opening on one end andincludes a hollow cavity 111 and a bottom 112. The hollow cavity 111 canreceive the diaphragm 150 and the damper 160. The bottom 112 can have acenter hole 113. The center pole 124 can be extended through the centerhole 113. The bottom 112 of the frame 110 can be fixed to the magneticcircuit 120.

The magnetic circuit 120 can include a lower plate 121, an upper plate122, a magnet 123, and a center pole 124. The magnet 123 can besandwiched by the lower plate 121 and the upper plate 122. The upperplate 122 and the magnet 123 can be circular, and define a substantiallycylindrical shaped space in the magnetic circuit 120. The center pole124 can be received in the substantially cylindrical shaped space andextend through the center hole 113. The center pole 124 can extend fromthe lower plate 121 to the upper plate 122 to define a magnetic gap 125with the magnet 123. The magnetic circuit 120 can be fixed on the bottom112 via the upper plate 122. The upper plate 122 can be fixed on thebottom 112 via adhesive or mechanical force. In one embodiment,according to FIG. 1, the upper plate 122 is fixed on the bottom 112 byscrews (not shown).

The voice coil 130 wound on the bobbin 140 can be a driving member ofthe loudspeaker 100. The voice coil 130 can be made of conducting wire.When the electric signals are input into the voice coil 130, thevariation of the electric signals can form a magnetic field. Theinteraction of the magnetic field caused by the voice coil 130 and themagnetic circuit 120 can produce the vibration of the voice coil 130.The vibration of the voice coil 130 causes the voice coil bobbin 140 tovibrate, which in turn, causes the diaphragm 150 fixed on the voice coilbobbin 140 to vibrate. The vibration of the diaphragm 150 causes theloudspeaker 100 to produce sound.

The bobbin 140 can be light in weight and have a hollow structure. Thecenter pole 124 can be disposed in the hollow structure and spaced fromthe bobbin 140. When the voice coil 130 vibrates, the bobbin 140 and thediaphragm 150 also vibrate with the voice coil 130 to produce sound.

The damper 160 has a through hole 161 therein to define an inner rim.The inner rim of the damper 160 can be fixed to the bobbin 140. An outerrim of the damper 160 can be fixed to the frame 110. Thus, the damper160 can mechanically hold the diaphragm 150 connected to the bobbin 140.The damper 160 can be a substantially ring-shaped plate having radiallyalternating circular ridges and circular furrows. Simultaneously, thedamper 160 can include a plurality of concentric rings. The ridges andthe furrows can be sawtooth shaped, wave shaped, involute shaped, orcombinations thereof. In one embodiment, the ridges and the furrows areinvolute shape. The damper 160 can be formed by means of hot pressing.The damper 160 can have a thickness of about 1 micrometer to about 1millimeter.

A plurality of conductive wires (not shown) can be disposed on thedamper 160. The connective wires can be fixed on the damper 160 viaadhesive or mechanical force. The conductive wires electrically connectthe voice coil 130 to a power source. When the voice coil 130 moves upand down, joints formed by the conductive wires voice coil 130 aredifficult to break, because a buffer is formed by the damper 160.

The diaphragm 150 is a sound producing member of the loudspeaker 100.The diaphragm 150 can have a conical shape when used in a large sizedloudspeaker 100. If the loudspeaker 100 has a smaller size, thediaphragm 150 can have a planar circular shape or a planar rectangularshape. In one embodiment, according to FIG. 3 and FIG. 4, the diaphragm150 has a conical shape. The peak or the center of the diaphragm 150 canbe fixed to the bobbin 140 via adhesive or mechanical force. An outerrim of the diaphragm 150 can be fixed to the frame 110. As shown in FIG.4, a contour of the diaphragm 150 has a domed central part and an edgepart integrally formed with the domed central part. The edge partextends outwardly and upwardly from a circular edge of the domed centralpart.

Referring to FIG. 4, the diaphragm 150 can include a carbon nanotubefilm structure 151 and an amorphous carbon structure 152 composited withthe carbon nanotube film structure 151 to form a stratiform compositestructure.

The carbon nanotube film structure 151 defines a plurality of micropores1511 as shown in FIG. 5. The carbon nanotube film structure 151 iscapable of forming a free-standing structure. The term “free-standingstructure” can be defined as a structure that does not have to besupported by a substrate. For example, a free-standing structure cansustain the weight of itself when it is hoisted by a portion thereofwithout any significant damage to its structural integrity. Thefree-standing structure of the carbon nanotube film structure 151 isrealized by the carbon nanotubes joined by van der Waals attractiveforce. So, if the carbon nanotube film structure 151 is placed betweentwo separate supporters, a portion of the carbon nanotube film structure151 not in contact with the two supporters, would be suspended betweenthe two supporters and yet maintain film structural integrity.

The carbon nanotube film structure 151 includes a plurality of carbonnanotubes uniformly distributed therein, and joined by van der Waalsattractive force therebetween. The carbon nanotubes in the carbonnanotube film structure 151 can be orderly or disorderly arranged. Theterm ‘disordered carbon nanotube film structure’ includes, but is notlimited to, a structure where the carbon nanotubes are arranged alongmany different directions, such that the number of the carbon nanotubesarranged along each different direction can be almost the same (e.g.uniformly disordered), and/or entangled with each other. ‘Ordered carbonnanotube film structure’ includes, but is not limited to, a structurewhere the carbon nanotubes are arranged in a consistently systematicmanner, e.g., the carbon nanotubes are arranged approximately along asame direction and or have two or more sections within each of which thecarbon nanotubes are arranged approximately along a same direction(different sections can have different directions). The carbon nanotubesin the carbon nanotube film structure 151 can be single-walled,double-walled, and/or multi-walled carbon nanotubes.

Macroscopically, the carbon nanotube film structure 151 may have asubstantially planar structure. The planar carbon nanotube structure canhave a thickness of about 0.5 nanometers to about 100 microns. Thecarbon nanotube film structure 151 includes a plurality of carbonnanotubes and defines a plurality of micropores 1511 having a size ofabout 1 nanometer to about 10 micrometers. The carbon nanotube filmstructure 151 includes at least one carbon nanotube film, the at leastone carbon nanotube film includes a plurality of carbon nanotubessubstantially parallel to a surface of the corresponding carbon nanotubefilm.

The carbon nanotube film structure 151 can include a flocculated carbonnanotube film as shown in FIG. 6. The flocculated carbon nanotube filmcan include a plurality of long, curved, disordered carbon nanotubesentangled with each other and can form a free-standing structure.Further, the flocculated carbon nanotube film can be isotropic. Thecarbon nanotubes can be substantially uniformly dispersed in the carbonnanotube film. The adjacent carbon nanotubes are acted upon by the vander Waals attractive force therebetween, thereby forming an entangledstructure with micropores 1511 defined therein. Alternatively, theflocculated carbon nanotube film is very porous. Sizes of the micropores1511 can be about 1 nanometer to about 10 micrometers. Further, due tothe carbon nanotubes in the carbon nanotube structure being entangledwith each other, the carbon nanotube film structure 151 employing theflocculated carbon nanotube film has excellent durability, and can befashioned into desired shapes with a low risk to the integrity of carbonnanotube structure. The flocculated carbon nanotube film, in someembodiments, will not require the use of structural support or due tothe carbon nanotubes being entangled and adhered together by van derWaals attractive force therebetween. The flocculated carbon nanotubefilm can have a thickness of about 0.5 nanometers to about 100 microns.

The carbon nanotube film structure 151 can include a pressed carbonnanotube film. The carbon nanotubes in the pressed carbon nanotube filmcan be arranged along a same direction or arranged along differentdirections. The carbon nanotubes in the pressed carbon nanotube film canrest upon each other. The adjacent carbon nanotubes are combined andattracted to each other by van der Waals attractive force, and can forma free-standing structure. An angle between a primary alignmentdirection of the carbon nanotubes and a surface of the pressed carbonnanotube film can be in a range from approximately 0 degrees toapproximately 15 degrees. The pressed carbon nanotube film can be formedby pressing a carbon nanotube array. The angle is closely related topressure applied to the carbon nanotube array. The greater the pressure,the smaller the angle. The carbon nanotubes in the carbon nanotube filmcan be substantially parallel to the surface of the carbon nanotube filmwhen the angle is about 0 degrees. A length and a width of the carbonnanotube film can be set as desired. The pressed carbon nanotube filmcan include a plurality of carbon nanotubes substantially aligned alongone or more directions. The pressed carbon nanotube film can be obtainedby pressing the carbon nanotube array with a pressure head.Alternatively, the shape of the pressure head and the pressing directioncan determine the direction of the carbon nanotubes arranged therein.Specifically, in one embodiment, when a planar pressure head is used topress the carbon nanotube array along the direction substantiallyperpendicular to a substrate. A plurality of carbon nanotubes pressed bythe planar pressure head may be sloped in many directions. In anotherembodiment, as shown in FIG. 7, when a roller-shaped pressure head isused to press the carbon nanotube array along a certain direction, thepressed carbon nanotube film having a plurality of carbon nanotubessubstantially aligned along the certain direction can be obtained. Inanother embodiment, when the roller-shaped pressure head is used topress the carbon nanotube array along different directions, the pressedcarbon nanotube film having a plurality of carbon nanotubessubstantially aligned along different directions can be obtained. Thepressed carbon nanotube film can have a thickness of about 0.5nanometers to about 100 microns, and can define a plurality ofmicropores 1511 having a diameter of about 1 nanometer to about 10micrometers.

In some embodiments, the carbon nanotube film structure 151 includes atleast one drawn carbon nanotube film as shown in FIG. 8. The drawncarbon nanotube film can have a thickness of about 0.5 nanometers toabout 100 microns. The drawn carbon nanotube film includes a pluralityof carbon nanotubes that can be arranged substantially parallel to asurface of the drawn carbon nanotube film. A plurality of micropores1511 having a size of about 1 nanometer to about 10 micrometers can bedefined by the carbon nanotubes. A large number of the carbon nanotubesin the drawn carbon nanotube film can be oriented along a preferredorientation, meaning that a large number of the carbon nanotubes in thedrawn carbon nanotube film are arranged substantially along the samedirection. An end of one carbon nanotube is joined to another end of anadjacent carbon nanotube arranged substantially along the samedirection, by van der Waals attractive force. More specifically, thedrawn carbon nanotube film includes a plurality of successively orientedcarbon nanotube segments joined end-to-end by van der Waals attractiveforce therebetween. Each carbon nanotube segment includes a plurality ofcarbon nanotubes substantially parallel to each other, and joined by vander Waals attractive force therebetween. The carbon nanotube segmentscan vary in width, thickness, uniformity and shape. A small number ofthe carbon nanotubes are randomly arranged in the drawn carbon nanotubefilm, and has a small, if not negligible, effect on the larger number ofthe carbon nanotubes in the drawn carbon nanotube film arrangedsubstantially along the same direction. The carbon nanotube film iscapable of forming a free-standing structure. The term “free-standingstructure” can be defined as a structure that does not have to besupported by a substrate. The free-standing structure of the drawncarbon nanotube film is realized by the successive segments joined endto end by van der Waals attractive force.

Understandably, some variation can occur in the orientation of thecarbon nanotubes in the drawn carbon nanotube film as can be seen inFIG. 8. Microscopically, the carbon nanotubes oriented substantiallyalong the same direction may not be perfectly aligned in a straightline, and some curve portions may exist. Furthermore, it can beunderstood that some carbon nanotubes located substantially side by sideand oriented along the same direction and in our contact with eachother.

Referring to FIG. 9, in one embodiment, the carbon nanotube filmstructure 151 includes a plurality of stacked drawn carbon nanotubefilms. The number of the layers of the drawn carbon nanotube films isnot limited. Adjacent drawn carbon nanotube films can be adhered by onlyvan der Waals attractive forces therebetween. An angle can exist betweenthe carbon nanotubes in adjacent drawn carbon nanotube films. The anglebetween the aligned directions of the adjacent drawn carbon nanotubefilms can range from about 0 degrees to about 90 degrees. In oneembodiment, the angle between the aligned directions of the adjacentdrawn carbon nanotube films is substantially 90 degrees, thus aplurality of substantially uniform micropores 1511 are defined by thecarbon nanotube film structure 151.

If the carbon nanotubes of the carbon nanotube film structure 151 arealigned along one direction or some predetermined directions, a largerstrength and Young's modulus can be achieved along the direction of thecarbon nanotubes in the carbon nanotube film structure 151. Therefore,by arranging the carbon nanotube film structure 151 to set the carbonnanotubes therein aligned along a particular direction, the strength andYoung's modulus of the diaphragm 150 along this direction can beimproved.

The amorphous carbon structure 152 can be infiltrated into themicropores 1511. “Amorphous carbon” is an allotrope of carbon that doesnot have any crystalline structure. The amorphous carbon has nolong-range crystalline order therein. A short-range order can exist, butwith deviations of the interatomic distances and/or inner-bonding angleswith respect to a graphite lattice as well as to a diamond lattice. Theamorphous carbon structure 152 can include a plurality of amorphouscarbon particles 1521 in the micropores 1511. The amorphous carbonparticles 1521 can be combined by covalent bonds therebetween. Theamorphous carbon particles 1521 can adhere to the carbon nanotubes orwarp the carbon nanotubes. Van der Waals attractive forces and covalentbonds therebetween can combine the amorphous carbon particles 1521 andthe carbon nanotubes. The covalent bonds can be an sp² hybridized bondor an sp³ hybridized bond between carbon atoms. A plurality of amorphouscarbon particles 1521 can also be disposed on opposite surfaces of thecarbon nanotube film structure 151 to form two amorphous carbon layers.Thus, the amorphous carbon structure 152 can wrap the carbon nanotubefilm structure 151. A cavernous shaped structure can be formed by theamorphous carbon structure 152. The carbon nanotube film structure 151can be embedded in the cavernous structure.

Both the carbon nanotubes of the carbon nanotube film structure 151 andthe amorphous carbon particles 1521 of the amorphous carbon structure152 are carbon materials. Thus, a density of the diaphragm 150 can besmaller. A higher energy conversion efficiency of the loudspeaker 100can be obtained. The carbon nanotubes and the amorphous carbon particles1521 are combined by the covalent bonds therebetween. A stress and atensility formed by the diaphragm 150 can be borne by most of the carbonnanotubes and the amorphous carbon particles 1521, when the diaphragm150 moves up and down with the bobbin 140. Thus, a larger strength andYoung's modulus of the diaphragm 150 can be achieved. A higher volume ofthe loudspeaker 100 can be obtained.

Referring to FIG. 10, another embodiment of a loudspeaker 200 is shown.The loudspeaker 200 can include a frame 210, a magnetic circuit 220, avoice coil 230, a bobbin 240, a diaphragm 250 and a damper 260.

The frame 210 can be mounted on an upper side of the magnetic circuit220. The voice coil 230 can be received in the magnetic circuit 220. Thevoice coil 230 can wind around the voice coil bobbin 240. An outer rimof the diaphragm 250 can be fixed to an inner rim of the frame 210, andan inner rim of the diaphragm 250 can be fixed to an outer rim of thebobbin 240 placed in the magnetic circuit 220. The diaphragm 250includes a carbon nanotube film structure and an amorphous carbonstructure composited with the carbon nanotube film structure to form astratiform composite structure. The magnetic circuit 220 includes alower plate 221, an upper plate 222, a magnet 223, and a center pole224. The magnet 223 is sandwiched by the lower plate 221 and the upperplate 222. The upper plate 222 and the magnet 223 are circular, anddefine a substantially cylindrical shaped space in the magnetic circuit220. The center pole 224 extends from the lower plate 221 to the upperplate 222 to define a magnetic gap 225 with the magnet 223.

The compositions, features and functions of the loudspeaker 200 in theembodiment shown in FIG. 10 are similar to the loudspeaker 100 in theembodiment shown in FIG. 1, except that the carbon nanotube filmstructure can include at least one carbon nanotube wire structure. Theat least one carbon nanotube wire structure can include a plurality ofcarbon nanotubes joined end to end by van der Waals attractive forcetherebetween along an axial direction. The at least one carbon nanotubewire structure includes one or more carbon nanotube wires. The carbonnanotube wires can be substantially parallel to each other to form abundle-like structure or twisted with each other to form a twistedstructure. The bundle-like structure and the twisted structure are twokinds of linear shaped carbon nanotube structure. The plurality ofcarbon nanotube wire structures can be woven together to form a planarshaped carbon nanotube structure. Referring to FIG. 11, the carbonnanotube film structure can include a plurality of carbon nanotube wirestructures, wherein some carbon nanotube wire structures can be arrangedalong the radial direction of the diaphragm 250, and the other carbonnanotube wire structures can be arranged to have a plurality ofhomocentric circular structures. The plurality of circular structuresand the diaphragm 250 can be homocentric with each other. Thus, thecarbon nanotube wire structures of carbon nanotube film structure can bewoven to together to form a cobweb shaped carbon nanotube structure.

The carbon nanotube wire can be untwisted or twisted. Treating the drawncarbon nanotube film with a volatile organic solvent can obtain theuntwisted carbon nanotube wire. In one embodiment, the organic solventcan be applied to soak the entire surface of the drawn carbon nanotubefilm. During the soaking, adjacent substantially parallel carbonnanotubes in the drawn carbon nanotube film will bundle together, due tothe surface tension of the organic solvent as it volatilizes, and thus,the drawn carbon nanotube film will be shrunk into an untwisted carbonnanotube wire. The untwisted carbon nanotube wire includes a pluralityof carbon nanotubes substantially oriented along a same direction (i.e.,a direction along the length direction of the untwisted carbon nanotubewire) as shown in FIG. 12. The carbon nanotubes are substantiallyparallel to the axis of the untwisted carbon nanotube wire. In oneembodiment, the untwisted carbon nanotube wire includes a plurality ofsuccessive carbon nanotubes joined end to end by van der Waalsattractive force therebetween. The length of the untwisted carbonnanotube wire can be arbitrarily set as desired. A diameter of theuntwisted carbon nanotube wire ranges from about 0.5 nanometers to about100 micrometers.

The twisted carbon nanotube wire can be obtained by twisting a drawncarbon nanotube film using a mechanical force to turn the two ends ofthe drawn carbon nanotube film in opposite directions. The twistedcarbon nanotube wire includes a plurality of carbon nanotubes helicallyoriented around an axial direction of the twisted carbon nanotube wireas shown in FIG. 13. In one embodiment, the twisted carbon nanotube wireincludes a plurality of successive carbon nanotubes joined end to end byvan der Waals attractive force therebetween. The length of the carbonnanotube wire can be set as desired. A diameter of the twisted carbonnanotube wire can be from about 0.5 nanometers to about 100 micrometers.

The carbon nanotube wire can be a free-standing structure. The lengthdirection of the carbon nanotube wire can have a larger strength andYoung's modulus. Therefore, by arranging the carbon nanotube wire to setthe carbon nanotube wire aligned substantially along a particulardirection, the strength and Young's modulus of the diaphragm 250 alongthis direction can be improved.

Referring to FIG. 14, one embodiment of a method for making thediaphragm 150, 250 can include following steps:

-   -   S10, providing a carbon nanotube film structure;    -   S20, soaking the carbon nanotube film structure with a polymer;        and    -   S30, carbonizing the carbon nanotube film structure infiltrated        in the polymer, the polymer being carbonized to an amorphous        carbon structure.

In step S10, the carbon nanotube film structure can be a free-standingstructure and define a plurality of micropores.

In step S20, the polymer can include a material of polyacrylonitrile,asphalt, viscose, phenolic, polyacrylate, polystyrene, polybutadiene, orcombination thereof. The polymer fills the micropores and composite withthe carbon nanotube film structure. The polymer and the carbon nanotubefilm structure can be combined by van der Waals attractive forces andcovalent bonds therebetween. The carbon nanotube film structure can bedipped into the solution with the polymer dissolved therein. Thus, thecarbon nanotube film structure can be soaked with the polymer. Thecarbon nanotube film structure can also be dipped in a solution with apre-polymer dissolved therein. The pre-polymer can be polymerized intothe polymer. Thus, the carbon nanotube film structure with the polymersoaked therein can be obtained. The pre-polymer can include a materialof acrylonitrile, ethyl acrylate, butyl acrylate, styrene, butadiene, orcombination of thereof.

In step S30, the polymer can be carbonized to the amorphous structure ina carbonization temperature. If the polymer is carbonized in a vacuum orin a place filled with inert gases, the carbonization temperature can belower than or equal to 1000° C. If the polymer is carbonized in normalatmosphere, the carbonization temperature can be lower than or equal to500° C. to prevent the carbon nanotubes from being oxidated. Theamorphous structure infiltrate into the carbon nanotube film structureand composite with the carbon nanotube film structure to form thediaphragm 150, 250.

It is to be understood that the above-described embodiments are intendedto illustrate rather than limit the present disclosure. Any elementsdescribed in accordance with any embodiments is understood that they canbe used in addition or substituted in other embodiments. Embodiments canalso be used together. Variations may be made to the embodiments withoutdeparting from the spirit of the disclosure. The above-describedembodiments illustrate the scope of the disclosure but do not restrictthe scope of the disclosure.

What is claimed is:
 1. A method for making a diaphragm, comprising:providing a carbon nanotube film structure, wherein the carbon nanotubefilm structure is a free-standing structure and defines a plurality ofmicropores; soaking the carbon nanotube film structure with a polymer toform a composite, wherein the soaking the carbon nanotube film structurewith the polymer comprises the polymer filling the plurality ofmicropores and combining with the carbon nanotube film structure, andthe polymer and the carbon nanotube film structure are combined by vander Waals attractive forces and covalent bonds therebetween; andcarbonizing the composite comprising the carbon nanotube film structureand the polymer at a carbonization temperature, the polymer beingcarbonized to form an amorphous carbon structure.
 2. The method asclaimed in claim 1, wherein the soaking the carbon nanotube filmstructure with the polymer comprises dipping the carbon nanotube filmstructure into a polymer solution comprising the polymer and a solvent.3. The method as claimed in claim 2, wherein the polymer is selectedfrom the group consisting of polyacrylonitrile, asphalt, viscose,phenolic, polyacrylate, polystyrene, and polybutadiene.
 4. The method asclaimed in claim 1, wherein the soaking the carbon nanotube filmstructure with the polymer comprises dipping the carbon nanotube filmstructure into a pre-polymer solution comprising a pre-polymer and asolvent and then polymerizing the pre-polymer to form the polymer. 5.The method as claimed in claim 4, wherein the pre-polymer is selectedfrom the group consisting of acrylonitrile, ethyl acrylate, butylacrylate, styrene, and butadiene.
 6. The method as claimed in claim 1,wherein the carbonization temperature is lower than or equal to 500° C.7. The method as claimed in claim 1, wherein the carbonizing thecomposite comprising the carbon nanotube film structure and the polymeris performed in a vacuum or inert gases atmosphere, and thecarbonization temperature is lower than or equal to 1000° C.
 8. Themethod as claimed in claim 1, wherein the amorphous carbon structureinfiltrates into the carbon nanotube film structure.
 9. The method asclaimed in claim 1, wherein the carbon nanotube film structure has acontour shape comprising a domed central part and an edge part that isintegrally formed with the domed central part; and the edge part extendsoutwardly and upwardly from a circular edge of the domed central part.10. A method for making a diaphragm, comprising: providing a carbonnanotube film structure comprising a plurality of carbon nanotubes anddefining a plurality of micropores therein; soaking the carbon nanotubefilm structure with a polymer to form a composite comprising the carbonnanotube film structure and the polymer; and carbonizing the polymer toform an amorphous carbon structure at a carbonization temperature,wherein the amorphous carbon structure comprises a plurality ofamorphous carbon particles, and the plurality of carbon nanotubescombines with the plurality of amorphous carbon particles by van derWaals attractive force and covalent bonds therebetween.
 11. The methodas claimed in claim 10, wherein the soaking the carbon nanotube filmstructure with the polymer comprises the polymer filling the pluralityof micropores and combining with the carbon nanotube film structure. 12.The method as claimed in claim 10, wherein the covalent bonds comprisean sp² hybridized bond or an sp3 hybridized bond between carbon atoms.13. The method as claimed in claim 10, wherein the plurality of carbonnanotubes is joined end-to-end by van der Waals attractive forcetherebetween.
 14. The method as claimed in claim 10, wherein thecarbonization temperature is lower than or equal to 500° C.